1. Field of the Invention
The present invention relates to a building material and method for manufacturing thereof, and more particularly to a building material in which a coating is applied to a front surface and a side surface exhibits a favorable adhesion property in relation to a sealing and method for manufacturing thereof.
2. Description of the Related Art
In a typical building material, front surface and rear surface of a base material are often coated to suppress variation in the physical properties of the building material due to water absorption, to improve weatherability, and to enhance the outer appearance.
Then, a plurality of the coated building materials is installed onto an outer wall or an inner wall of a house or the like to form a wall surface. At this time, spaces are often provided between vertically and/or horizontally adjacent building materials at constant intervals using a joiner, a backup material, or the like, and a waterproof, flexible rubber elastic sealing constituted by a polymer such as silicone, modified silicone, polyurethane, or polysulfide is charged into the spaces to join the adjacent building materials. The dimensions of building boards vary over time, and by charging a sealing in this manner, temporal variation in the building boards can be dealt with (see Japanese Unexamined Patent Application Publication No. 2003-343024).
However, when a coating film is formed on the side surface of the building material, the sealing that is adhered to the coating film may peel away when the coating film peels away from the side surface.
When the sealing peels away from the building material, a gap forms between the building material and the sealing, and rainwater infiltrates the gap. The infiltrating rainwater is absorbed through the side surface of the building material, causing the physical properties of the building material to deteriorate, and when the rainwater spreads over the rear surface side of the building material, members other than the building material are adversely affected thereby.
To make the sealing less likely to peel away from the building material, a coating film need not be formed on the side surface of the building material. However, when the front surface of the building material is coated, the coat applied to the front surface often spreads to the side surface such that an unwanted coating film is formed on the side surface.
When the front surface of the building material is coated using a coating method such as spraying or flow coating, the side surface is particularly likely to be coated in the coat, leading to the formation of an unwanted coating film.